KENTUCKY (9/24/13) – Until recently, obesity was considered solely the result of overeating and/or too little activity. However, recent studies have shown that bacteria or, rather, the lack of the certain types of bacteria, can factor in a person's weight.

Dr. Kristine Krueger, head of gastroenterology, hematology and nutrition for the University of Louisville, said new research into the role of the microbiota is opening the door to better understanding of diseases including obesity.

"Bacteria are important in helping assimilate the nutrients in our food," said Krueger. "If we don't have the right bacteria or enzymes, we don't process our food."

Krueger said universities and academic centers have been studying treatments using good bacteria. While it's not a commonly-known practice, the federal Food and Drug Administration has approved the use of fecal microbiota transfers, or FMTs, for the treatment of severe diarrhea.

"An example of using good bacteria is stool transfers from a healthy donor that can stabilize the gut microbiota in a sick person," said Krueger. "It could be that in the future, the FDA might approve the FMTs for the treatment of obesity."

Transfer of bacteria from obese animals into thin animals has resulted in the thinner animals gaining weight, said Krueger. Human research has involved transferring microbiota from thin people to obese people.

The result? They lost weight, she said.

A person that doesn't have the adequate gut bacteria may absorb carbohydrates more easily that a thin person, said Krueger.

"The result may be that one person gains more weight from that piece of coffee cake than the other," she said. "We need to be in harmony with our gut bacteria to help us get the proper nutrition and vitamins. When all of that is out of whack, or dysbiosis, we won't absorb nutrients properly."

Since the FDA has not approved FMTs for the treatment of obesity, what can be done now to achieve the optimum level of colon bacteria?

"Avoid taking too many antibiotics," said Krueger. "While it might kill certain bacteria, it might kill the good kind, too."

Krueger said everyone should refrain from asking for antibiotics unless their physician believes it's absolutely necessary.

Another tactic for achieving the proper balance of gut bacteria is to eat foods rich in them like Greek yogurt, she said. Other sources including probiotics in pill form should contain both lactobacilli and bifidobacili.

And, high fat diets can hinder the development of healthy bacteria, said Krueger.

"Some data indicates that a high fat diet alters microbiota and makes it the more unfavorable type," she said.

So, ingesting foods or pills with a variety of good bacteria, limiting bacteria killing antibiotics unless totally necessary and controlling the amount of fat in the diet are ways of helping to control obesity, said Krueger.

"We know that we can do FMTs now that will affect obesity," she said. "But, I can't predict when it will be available as a treatment for it."